- The US Food and Drug Administration (FDA) approved the first PI3K inhibitor alpelisib to be taken in combination with fulvestrant in PIK3CA-mutated hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−) advanced or metastatic breast cancer that has progressed while on or after receiving endocrine therapy.
- FDA also approved a companion diagnostic test for detection of PIK3CA mutations in tissue and/or liquid biopsy, the therascreen PIK3CA RGQ PCR Kit.
Why this matters
- Alpelisib is the first new treatment option for women and men with PIK3CA mutations, which are common in this type of breast cancer.
- Prescribing information is here.
- Approval comes within the same week as publication of the SOLAR-1 trial in the New England Journal of Medicine.
- The SOLAR-1 trial (n=572 women and men) found that addition of alpelisib to fulvestrant extends PFS (median of 11 vs 5.7 months) in PIK3CA-mutated, HR+/HER2− advanced or metastatic breast cancer.
- The most common adverse effects were hyperglycemia, increase in creatinine, diarrhea, rash (which can be severe), decrease in blood lymphocyte count, and elevated liver enzymes, among others.
- The FDA advises clinicians to check fasting glucose and HbA1c, and to optimize glycemic control before starting treatment.
- Patients also should be monitored for pneumonitis/interstitial lung disease and diarrhea.